J. Berglund et Li. Elding, MANGANESE-CATALYZED AUTOXIDATION OF DISSOLVED SULFUR-DIOXIDE IN THE ATMOSPHERIC AQUEOUS-PHASE, Atmospheric environment, 29(12), 1995, pp. 1379-1391
Autoxidation of SO2(aq) in the presence of manganese(II) is one of the
important pathways for sulfuric acid formation in atmospheric clouds
and fogs. Recent experimental results indicating that the catalyzed re
action takes place via a complex free-radical mechanism are discussed.
Previous literature is reviewed in the light of this mechanism. Under
atmospheric conditions of low total concentrations of manganese(II) (
less than or equal to 2 x 10(-5) M) and sulfur(IV) (less than or equal
to 10(-5) M) and 2.5 <pH < 5, the rate law for conversion of SO2(aq)
to SO3(aq) is reduced to d[S(IV)]/dt = k[Mn(II)][S(IV)], where [S(IV)]
denotes the total concentration. A value of the overall rate constant
k of 1.4 x 10(3) M(-1)s(-1) is recommended for use in atmospheric mod
el calculations.